Kwargs: assert functions (#6406)

Closes https://github.com/KittyCAD/modeling-app/issues/6408

rust/kcl-lib/tests/computed_var/input.kcl

@@ -5,14 +5,15 @@ arr = [0, 0, 0, 10]
 i = 3
 ten = arr[i]
 
-assertEqual(ten, 10, 0.000001, "oops")
+assert(ten, isEqualTo = 10, error = "oops")
 
 p = "foo"
 obj = { foo = 1, bar = 0 }
 one = obj[p]
 
-assertEqual(one, 1, 0.0000001, "oops")
+assert(one, isEqualTo = 1, error = "oops")
+
+assert(PI, isEqualTo = 3, tolerance = 0.2, error = "oops pi")
 
-assertEqual(PI, 3, 0.2, "oops pi")
 x = cos(2 * PI)
-assertEqual(x, 1, 0.000001, "oops cos")
+assert(x, isEqualTo = 1, tolerance = 0.000001, error = "oops cos")